Grifball will be officially included in Halo 4, 343 Industries has confirmed.
The multiplayer mode's origins stretch back to machinima series Red vs. Blue’s fourth season, where an offhand comment by a character about the game spawned a playable community-created version of it.
In the game – which somewhat resembles a very simple game of weaponised rugby – teams attempt to carry a ball into a goal while avoiding hammer and sword attacks from the opposition. The ball may be passed to teammates using the game's grenade lobbing mechanic.
In related news, Halo 4's Oddball mode is to feature the same grenade-throw mechanic as Grifball, and Capture the Flag mode will now allow the player carrying the flag to wield a “flagnum” in one hand while using the flag itself as a melee weapon with the other.
Halo 4 is due out on November 6 on the Xbox 360.